1. Field of the Invention
The present invention relates to a developing device and an image forming device. More specifically, the present invention relates to an improvement for preventing leaking of developing agent.
2. Description of the Related Art
A prior art device in which leak preventing members for developing agent (including toner and carrier) are provided in the vicinity of both ends of a developing roller is known. In this prior art device, the leak preventing member for the developing agent includes a side seal as a base member and felt as an uppermost layer.
A cleaning blade is used for scraping out remaining toner adhered on a photosensitive body. Blade end seals are fixed to ends of the cleaning blade with respect to the longitudinal direction thereof.
A structure of the developing device in the prior art will be described as an example. FIG. 8 is a cross-sectional view showing the structure in the vicinity of an end of a developing roller 42 that defines the developing device with respect to the longitudinal direction thereof. FIG. 9 is a perspective view showing the structure in the vicinity of the end of the developing roller 42 with respect to the longitudinal direction. As shown in FIG. 8 and FIG. 9, the developing device mainly includes the developing roller 42, a blade 61, a bracket 62 and a seal member 63. The developing roller 42, the blade 61, the bracket 62 and the seal member 63 are stored in a housing (not shown) of the developing device.
The developing roller 42 is a rotating roller for causing the developing agent to adhere on an outer surface of the developing roller 42 by a magnetic force. The blade 61 is a regulating member for regulating the layer thickness of the developing agent adhered on the outer surface of the developing roller 42. As shown in FIG. 9, the blade 61 is provided in parallel with the longitudinal direction of the developing roller 42.
The bracket 62 supports the blade 61. As shown in FIG. 9, the bracket 62 is longer than the length of the blade 61 in the longitudinal direction. The blade 61 is mounted to the bracket 62 so that a protrusion 61d protrudes toward the developing roller 42 as shown in FIG. 9.
The seal member 63 is a member for preventing the developing agent from leaking from positions near the ends of the developing roller 42 with respect to the longitudinal direction. As shown in FIG. 9, the seal member 63 is provided in the vicinity of the end of the developing roller 42 with respect to the longitudinal direction. As shown in FIG. 8, the seal member 63 is mounted on an inner surface 43a of the housing so that the height of an upper end surface of the seal member 63 is substantially flush with the height of a lower surface of the bracket 62.
However, the developing device having the structure as described above has the following problem. That is, as shown in FIG. 9, a gap 61b is defined at a position surrounded by the outer surface of the developing roller 42, the protrusion 61d of the blade 61, the bracket 62 and the seal member 63. Consequently, the developing agent leaks from the gap 61b. 